﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections;
using System.ComponentModel;

namespace System.Windows.Forms;

public class PropertyManager : BindingManagerBase
{
    private object? _dataSource;
    private readonly string? _propName;
    private PropertyDescriptor? _propInfo;
    private bool _bound;

    /// <summary>
    ///  An object that represents the object to which the property belongs.
    /// </summary>
    public override object? Current => _dataSource;

    private void PropertyChanged(object? sender, EventArgs ea)
    {
        EndCurrentEdit();
        OnCurrentChanged(EventArgs.Empty);
    }

    private protected override void SetDataSource(object? dataSource)
    {
        if (_dataSource is not null && !string.IsNullOrEmpty(_propName))
        {
            _propInfo?.RemoveValueChanged(_dataSource, PropertyChanged);
            _propInfo = null;
        }

        _dataSource = dataSource;

        if (_dataSource is not null && !string.IsNullOrEmpty(_propName))
        {
            _propInfo = TypeDescriptor.GetProperties(_dataSource).Find(_propName, true);
            if (_propInfo is null)
            {
                throw new ArgumentException(string.Format(SR.PropertyManagerPropDoesNotExist, _propName, dataSource));
            }

            _propInfo.AddValueChanged(_dataSource, PropertyChanged);
        }
    }

    public PropertyManager()
    {
    }

    internal PropertyManager(object dataSource) : base(dataSource)
    {
    }

    internal PropertyManager(object? dataSource, string propName) : base()
    {
        _propName = propName;
        SetDataSource(dataSource);
    }

    internal override PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[]? listAccessors)
    {
        return ListBindingHelper.GetListItemProperties(_dataSource, listAccessors);
    }

    internal override Type BindType => _dataSource!.GetType();

    internal override string GetListName()
    {
        return $"{TypeDescriptor.GetClassName(_dataSource!)}.{_propName}";
    }

    public override void SuspendBinding()
    {
        EndCurrentEdit();
        if (_bound)
        {
            try
            {
                _bound = false;
                UpdateIsBinding();
            }
            catch
            {
                _bound = true;
                UpdateIsBinding();
                throw;
            }
        }
    }

    /// <summary>
    ///  Resumes data binding.
    /// </summary>
    public override void ResumeBinding()
    {
        OnCurrentChanged(EventArgs.Empty);
        if (!_bound)
        {
            try
            {
                _bound = true;
                UpdateIsBinding();
            }
            catch
            {
                _bound = false;
                UpdateIsBinding();
                throw;
            }
        }
    }

    /// <summary>
    ///  Gets the name of the list supplying the data for the binding.
    /// </summary>
    /// <returns>Always returns an empty string.</returns>
    protected internal override string GetListName(ArrayList? listAccessors) => string.Empty;

    /// <summary>
    ///  Cancels the current edit.
    /// </summary>
    public override void CancelCurrentEdit()
    {
        IEditableObject? obj = Current as IEditableObject;
        obj?.CancelEdit();
        PushData();
    }

    /// <summary>
    ///  Ends the current edit.
    /// </summary>
    public override void EndCurrentEdit()
    {
        PullData(out bool success);

        if (success)
        {
            IEditableObject? obj = Current as IEditableObject;
            obj?.EndEdit();
        }
    }

    protected override void UpdateIsBinding()
    {
        for (int i = 0; i < Bindings.Count; i++)
        {
            Bindings[i].UpdateIsBinding();
        }
    }

    /// <summary>
    ///  Raises the <see cref="BindingManagerBase.CurrentChanged" /> event.
    /// </summary>
    /// <param name="ea">The event data.</param>
    protected internal override void OnCurrentChanged(EventArgs ea)
    {
        PushData();

        onCurrentChangedHandler?.Invoke(this, ea);
        _onCurrentItemChangedHandler?.Invoke(this, ea);
    }

    /// <summary>
    ///  Raises the <see cref="BindingManagerBase.CurrentItemChanged" /> event.
    /// </summary>
    /// <param name="ea">The event data.</param>
    protected internal override void OnCurrentItemChanged(EventArgs ea)
    {
        PushData();

        _onCurrentItemChangedHandler?.Invoke(this, ea);
    }

    internal override object? DataSource => _dataSource;

    internal override bool IsBinding => _dataSource is not null;

    /// <summary>
    ///  Gets the position in the underlying list that controls bound to this data source point to.
    /// </summary>
    /// <value>Always returns 0.</value>
    public override int Position
    {
        get => 0;
        set
        {
        }
    }

    /// <summary>
    ///  Gets the number of rows managed by the <see cref="BindingManagerBase" />.
    /// </summary>
    /// <value>Always returns 1.</value>
    public override int Count => 1;

    /// <summary>
    ///  Throws a <see cref="NotSupportedException" /> in all cases.
    /// </summary>
    /// <exception cref="NotSupportedException">In all cases.</exception>
    public override void AddNew()
    {
        throw new NotSupportedException(SR.DataBindingAddNewNotSupportedOnPropertyManager);
    }

    /// <summary>
    ///  Throws a <see cref="NotSupportedException" /> in all cases.
    /// </summary>
    /// <param name="index">The index of the row to delete.</param>
    /// <exception cref="NotSupportedException">In all cases.</exception>
    public override void RemoveAt(int index)
    {
        throw new NotSupportedException(SR.DataBindingRemoveAtNotSupportedOnPropertyManager);
    }
}
